In the color spread for chapter 33, five celebration dates were announced. People tweet 5toubun hashtags and if it reaches a certain number of tweets by the end of the day, we get a prize from negi. They also encourage to post fanart and thoughts on the manga and ideas for future chapters. The goal for the first holiday a couple months ago was 5555 tweets but they only got about 4.1k. Next toubun holiday is on 8/8. Next one is in October I think, 4th one is on new years, last one is sometime in march.